Browsing by Subject "shelf"
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Item Evaluation of a Deep Plan Office Space Daylit with an Optical Light Pipe and a Specular Light Shelf(2009-05-15) Upadhyaya, KapilThis research developed the Optical Light Pipe (OLP) as a feasible solution to solve the problem of insufficient daylighting in deep plan office spaces for predominantly sunny climates. It further combined the OLP with a Specular Light Shelf (SLS) to achieve uniform daylighting. This research was performed with an experimental setup of two 1:4 scale models of deep plan office spaces, modified from an earlier research on optical light pipe at College Station, TX. Blinds and shading devices were installed on the south fa?ade to provide daylight to the front zone of a 20 feet by 30 feet office module. The back zone was daylit by the OLP hidden in the plenum. The existing OLP design was optimized through computer aided ray-tracing. The SLS design was based on an earlier prototype designed at Lawrence Berkeley National Labs (LBNL). Results were based on observations made on clear and cloudy sky days between February 3rd and March 17th. The OLP achieved more than 300 lux of average workplane illuminance for 7.4 hours, when global horizontal illuminance was greater than 40,000 lux. It also achieved 200 lux of illuminance higher than an earlier prototype (Martins-Mogo, 2005) on workplane between 1000hrs and 1630hrs. It exhibited a glare free daylight distribution with luminance ratios well within prescribed limits on most of the vertical surfaces, with a relatively uniform illuminance distribution on back taskplane. OLP was better than windows with blinds and shading at providing diffuse daylight in backzone on a cloudy day, when global horizontal illuminance was greater than 20,000 lux. The OLP used in combination with SLS achieved more than 500 lux of average workplane illuminance for 6 hours, when global horizontal illuminance was greater than 40,000 lux. SLS also produced more uniform illuminance levels on the workplane at all times and on the leftwall at most times. However, it produced non-uniform luminance distribution on walls and ceiling and luminance ratios higher than allowable limits on the sidewall for some morning hours, and hence needed further refinement in design.Item The Relationships of Particulate Matter and Particulate Organic Carbon with Hypoxic Conditions Along the Texas-Louisiana Shelf(2014-08-06) Zuck, Nicole AThe Mississippi-Atchafalaya river system discharges into the northern Gulf of Mexico and peaks during the spring freshet bringing high levels of nutrients that spur eutrophication in surface waters, often resulting in hypoxic (dissolved oxygen concentrations less than 1.4 mL/L) sub-pycnocline conditions. Hypoxia is generally manifest seasonally along the Louisiana coast over the shelf. In summer 2011, high rainfall in the Mississippi-Atchafalaya watershed caused high discharge into the northern Gulf of Mexico. In summer 2012 drought conditions in the watershed significantly reduced the discharge. Summer 2013 conditions returned to the climatologic average river discharge. Discrete samples were collected and continuous measurements were made via an onboard surface-water flow-through system, CTD casts, and by an undulating towed vehicle. Total particulate matter and particulate organic carbon samples were obtained from Niskin bottles on CTD casts. Samples were also taken to measure dissolved oxygen concentration and nutrients along with other hydrographic parameters. Water-column particulate matter and particulate organic carbon were analyzed to investigate the relationship between hypoxia and the composition of the particulate matter along the Texas-Louisiana shelf during different discharge rates in summer 2011 (for C:N of particulate matter), 2012 and 2013 for a larger suite of particle composition and relationship to hydrographic conditions of the Mississippi-Atchafalaya river system. The goal of this research is to determine if a statistically significant relationship is manifest, between shelf hypoxia and total particulate matter, as well as between particulate organic carbon and hypoxia, during periods of different river discharge (i.e. average, flood, or drought conditions). Correlations were identified between some variables, but no direct relationship between particulate matter and hypoxia was observed. There were however, some statistically significant changes in several parameters between summer 2013 and summer 2013.